Calcium‐dependent contractile response of arterial smooth muscle to a jellyfish toxin (pCrTX: Carybdea rastonii)

Abstract

1 The purpose of the present experiments was to investigate the pharmacological mechanisms of the vasoconstriction caused by the toxin (pCrTX) which had been partially purified from the tentacles of the jellyfish Carybdea rastonii ('Andonkurage').2 pCrTX (0.1 to 10 ptg ml'-l) produced a tonic contraction of rabbit aortic strips, which was nearly abolished in Ca2+-free medium and was significantly reduced by verapamil or diltiazem. 3 pCrTX stimulated 45Ca2+-influx and this effect was markedly attenuated by verapamil. 4 pCrTX-induced vasoconstriction was significantly attenuated by phentolamine, 6-hydroxydopamine (6-OHDA) and in low Na'-medium, but not by bretylium, guanethidine, reserpinization or tetrodotoxin (TTX). 5 pCrTX continuously and significantly increased the 3H-efflux from [3H1-noradrenaline preloaded aortic strips and this effect was completely inhibited by pretreatment with 6-OHDA and in Ca2+-free medium, but not by phentolamine, bretylium, guanethidine or TTX.6 A single exposure to pCrTX for 30min greatly reduced the contractile responses to tyramine, nicotine and transmural electrical stimulation, but not those to noradrenaline or KC1. In addition, incorporation of [3HJ-noradrenaline was reduced.7 Pretreatments with chlorphenylamine or indomethacin failed to modify the contractile response to pCrTX. 8 These results suggest that the pCrTX-induced vasoconstriction is caused by a presynaptic action, releasing noradrenaline from the intramural adrenergic nerve terminals, and by a postsynaptic action, which consists at least in part of stimulation of the transmembrane calcium influx. Both pre-and postsynaptic actions depend on the external calcium concentration. The data further suggest that pCrTX damages the noradrenaline uptake and/or storage mechanisms without damaging postsynaptic contractile systems.

Novel Proteinaceous Toxins from the Box Jellyfish (Sea Wasp) Carybdea rastoni

“…pCrTX has also been reported to cause contractions in rabbit aorta by releasing norepinephrine from adrenergic nerve terminals and by increasing the transmembrane Ca 2ϩ influx (21). Furthermore, pCrTX relaxes norepinephrine-induced contractions in rat aorta, and this may be due to the release of an endothelium-derived relaxing factor (22).…”

Cutaneous Reactions Caused by Experimental Exposure to Jellyfish, Carybdea rastonii

“…It is well-documented that these substances have physiological and toxicological effects such as lethal toxicity on mammals, hemolytic activity, dermonecrotic activity, and cardiotoxic effects (2). Beside these toxic effects, allergic mechanisms may play a role in the general reactions caused by jellyfish stings.…”

Contractile Effects of Jellyfish Toxin Extracted from Carybdea rastonii on Isolated Rabbit Aorta

“…Our previous report showed that the pCrTX-induced contraction was partially in hibited by verapamil (2). In the present experiment, we re-examined this in the tissue from which adventitia and endothelium had been removed.…”

“…A toxic component extracted from the tentacles of the jellyfish (pCrTX) has been shown to induce platelet aggregation (1 ). pCrTX has also been reported to cause a contraction in rabbit aorta by releasing noradrenaline from adrenergic nerve terminals and by increasing transmembrane Ca 21 influx (2) and to inhibit the contraction in rat aorta by releasing a relaxant substance from the endothelium (3).…”